1968 Error Nickel

Depends on the grade. If it is circulated, 1968 is not a hard date to find offstruck coins, and it might be worth $35. Certainly worth at least three times that if uncirculated (MS-60 to MS-63). If higher grades (e.g., MS-64), then it depends partially on eye-appeal and demand, but gem mint state versions can fetch $200 or more in an auction.

Lastly, take a pair of pliers and pinch down those staples on the 2x2 flip... you don't want them scratching other coins.